#javascript

addListeners

/**
 * Add event listeners on an `EventEmitter` using a map of <event, listener>
 * pairs.
 *
 * @param {EventEmitter} server The event emitter
 * @param {Object.<String, Function>} map The listeners to add
 * @return {Function} A function that will remove the added listeners when called
 * @private
 */
function addListeners(server, map) {
  for (const event of Object.keys(map)) server.on(event, map[event]);

  return function removeListeners() {
    for (const event of Object.keys(map)) {
      server.removeListener(event, map[event]);
    }
  };
}

/**
 * Check if it's hidden.
 */

function isHidden (root, path) {
  path = path.substr(root.length).split(sep)
  for (let i = 0; i < path.length; i++) {
    if (path[i][0] === '.') return true
  }
  return false
}

// 查看请求体是否有内容

var hasBody = function(){
	// tranfser-encode: chunk: 分块编码
	return 'transfer-encoding' in req.headers || 'content-length' in req.headers
}

// hasOwnProperty 获取对象自有属性
function hasOwnProperty(obj, prop) {
  return Object.prototype.hasOwnProperty.call(obj, prop);
}

// 读取 pkg.json
// check if the directory is a package.json dir
var packageMainCache = {};

function readPackage(requestPath) {
  if (hasOwnProperty(packageMainCache, requestPath)) {
    return packageMainCache[requestPath];
  }

  try {
    var jsonPath = path.resolve(requestPath, 'package.json');
    var json = fs.readFileSync(jsonPath, 'utf8');
  } catch (e) {
    return false;
  }

  try {
    var pkg = packageMainCache[requestPath] = JSON.parse(json).main;
  } catch (e) {
    e.path = jsonPath;
    e.message = 'Error parsing ' + jsonPath + ': ' + e.message;
    throw e;
  }
  return pkg;
}

// require.js 源码

https://github.com/nodejs/node-v0.x-archive/blob/master/lib/module.js